A Model of Grassroots Changes in Linguistic Systems

People converge on linguistic norms by imitating each other. The value of these norms derives more from their existence than from their specifics; agreement on ways of referring to entities, events, and abstractions enables people to pool individual knowledge and organize large-scale cooperation. In this regard, language resembles products such as fax machines, Facebook, or team sports equipment, whose utility depends strongly on the extent to which other people have adopted the same product.

Once consensus on a norm is reached, why would it ever change? This question, a central one in social dynamics, is especially challenging in relation to linguistic systems. Many linguistic innovations seem to be completely arbitrary, and furthermore most changes originate with ordinary people. Empirical studies show that high status people are typically the last to adopt innovative forms, which means that they do not have the role of "influentials" in promoting the change.

In this talk, I will present a new model (developed together with NICO alums Robert Daland and Forrest Stonedahl) for the adoption of the most theoretically intractable class of linguistic innovations: innovations that are arbitrary (in that they offer no global functional advantage), fast (taking place within the lifetimes of individuals), and egalitarian (typically originating with ordinary people). The mechanism, which involves the interaction of social and cognitive factors, is a previously unsuspected regime for informational cascades in social networks. The same mechanism may also be relevant for other grassroots changes in social norms.

Bio

Janet B. Pierrehumbert is Professor of Linguistics at Northwestern University and Adjunct Professor at the New Zealand Institute of Language Brain and Behaviour, University of Canterbury. She received her B.A from Harvard in 1975, and her Ph.D from MIT in 1980. She was a Member of Technical Staff at AT&T Bell Labs in Linguistics and AI Research until 1989, when she joined the Northwestern faculty.

Pierrehumbert's research program focuses on the ways in which the dynamics of language -- in acquisition, processing, or historical change -- relate to the structure of linguistic systems. It combines experiments, statistical analyses of large corpora, and computational simulations of linguistic communities. It has been funded by the NSF, NIH, IARPA, the James S. McDonnell Foundation, and the John Templeton Foundation.

Pierrehumbert is a Fellow of the Guggenheim Foundation, the Linguistic Society of America, the Cognitive Science Society, and the American Academy of Arts and Sciences.